The European Aviation Safety Agency (EASA) published a proposal to update the Certification Specifications for large aeroplanes and turbine engines for flights in icing conditions.

The proposed Certification Specifications update aim at better protecting large aeroplanes and turbine engines when flying in atmospheric icing conditions. Icing environments such as freezing rain and freezing drizzle (Supercooled Large Drops), ice crystals and mixed phases, only partly covered in the existing Certification Specifications, will be taken into account in the updated proposal. EASA also proposes a revision of the requirements for engine air intake de-icing and anti-icing systems with an update of the freezing fog conditions and the introduction of falling and blowing snow conditions.

This new proposal includes EASA’s analysis of the recommendations made in 2009 by the Ice Protection Harmonization Working Group and the service experience gathered from large aeroplanes and turbine engines operations over the past 15 years. In particular, the group has outlined an evolution over the years of atmospheric conditions at flying altitude and the need to take into account these new weather environments.

The amendment of the certifications specifications for large aeroplanes (CS-25) and for turbine engines (CS-E) is expected to enter into force during the second quarter of 2012, after a period of public consultation and comments. Manufacturers of large aeroplanes and turbine engines will then have to comply with these updated rules.

The Ice Protection Harmonization Working Group is an international group that was tasked by the FAA Aviation Rulemaking Advisory Committee (ARAC) in 1997 to prepare recommendations for regulation change on the topic of flight in icing conditions. The proposed Certification Specifications update is fully harmonized with those of the FAA adopted in 2009.

The proposed regulations would improve safety by addressing supercooled large drop icing conditions for transport category airplanes most affected by these icing conditions, mixed phase and ice crystal conditions for all transport category airplanes, and supercooled large drop, mixed phase, and ice crystal icing conditions for all turbine engines. These proposed regulations are the result of information gathered from a review of icing accidents and incidents.